1. Technical Field
The present disclosure relates to packaging structures for semiconductor devices, particularly to an interposer and a package on package (POP) structure including the interposer.
2. Description of Related Art
In order for a POP structure to attain a high density integrated layout and a small area installation, two electric elements are electrically connected by a plurality of solder balls. The diameter of the solder ball may be in the range from 200 um to 300 um which is quite large. It is difficult to reduce the volume of the POP structure due to the large diameters of the solder ball and the large size of contact pad corresponding to the solder ball. The structural strength and integrity of the connection between the solder ball and the contact pad is not optimal due to the large diameter of the solder ball. So, the reliability of POP structure is not good. In addition, the bottom one of the two electric elements is usually provided between two circuit boards. Heat created by the bottom electric elements is hard to dissipate due to undesirable insulation given by the two circuit boards.
What is needed, therefore, is a POP structure that can overcome the described limitations.